Digital signal processing (DSP) is used in a variety of digital systems to achieve high performance at low manufacturing costs. The benefits of DSP can be extended to systems incorporating phase detectors, such as receivers and measurement systems, that receive and phase compare analog signals, but effective use of DSP in these systems depends on first obtaining a digital representation of the compared phase. However, finite quantization steps in any digital representation of the analog phase difference introduce nonlinearities similar to those inherent in analog-to-digital converters (ADCs) used to digitize the amplitudes of analog signals. Amplitude dithering, a known linearization technique for ADCs, is based on adding noise to the amplitude of the applied analog signal. Sufficient random amplitude variation is introduced by the added noise to overcome nonlinearities caused by the quantization steps. However, amplitude dithering is ineffective at linearizing phase detectors which respond to the relative phases of applied analog signals. Accordingly, there is a need for a phase detector that produces a digital output having a linear relationship to the phase difference between the applied analog signals.